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Patented Feb. 20, 1934 UNITED STATES PROCESS FOR OBTAINING SECONDARY ALCOHOLS FROM AoID'LIoUOR's FORMED BY TREATING OLEFINES WITH SUL- PHURIC ACID Benjamin T. Brooks, Greenwich, Conn., assignor, by mesne assignments, to" Standard Alcohol Company, Wilmington, Del.,a'corporation of Delaware NO Drawing. Application May 3, 1932 Serial No. 609,036

4 Claims. (01. 26o 1'56') The invention will be fully understood from the following description:

The secondary alcohols of from 3 to 6 carbon atoms to the molecule are produced commercially by the sulphation of olefines followed by the hydrolysis of the alkyl sulphates so produced and the separation of the alcohol by distillation. The olefine material may be obtained by the destructive distillation of a variety of hydrocarbon substances, but the preferred source is the light fraction of the material formed by cracking petroleum oil. A preferred method of generating the olefine material is vapor phase cracking of petroleum oil carried out at a temperature between 1050 and 1150 F. The sulphation is preferably carried out by the application of aqueous sulphuric acid to a close out olefine fraction containing preferably the normal olefines of a single number of carbon atoms to the molecule, as for example a propylene, butylene or amylene fraction separated by rectification of the products of cracking, thereby forming the alkyl sulphates corresponding to the normal olefines present in the fraction.

Alternatively, however, sulphation reaction may be carried out by the application of aqueous sulphuric acid to a broader fraction containing 2 or more different normal olefines together with such other hydrocarbons as are normally present in a fraction separated by rectification from cracked petroleum. The sulphation treatment may be carried out by contacting sulphuric acid with the olefine material in gaseous condition, as for example by running them counter-currently through a tower containing the plates or packing necessary to permit intimate contact between gas and vapor, in which case the acid liquor is withdrawn from the lower part of the tower. Alternatively, the sulphation may be carried out by contacting a liquid fraction with aqueous sulphuric acid in a suitable agitator. When made by any of the processes mentioned, however, the acid liquor contains considerable hydrocarbon material, principally polymerized hydrocarbons formed during the reaction. The polymers tend to separate on standing but the separation is slow and incomplete, and holding the acid liquor in concentrated condition results in a decrease in alcohol yield owing to the continuous formation of polymers. This is particularly the case where the acid liquor contains the alkyl sulphates corresponding to butyl, amyl and hexyl alcohols. The preferred procedure is, therefore, to dilute the acid liquor with water as soon as practicable, thereby arresting the polymerization. The diluted acid liquor may be distilled for the separaabove the aqueous layer containing secondary alcohol and sulphuric acid. The hydrocarbon layer is then carefully separated from the aque'- ous layer, and the aqueous layer is separately distilled for the recovery of' its alcohol content. The hydrocarbon layer contains considerable secondary alcohols, how-' ever, as the alcohol partitions itself between the aqueous and oil layers; and it is therefore necessary to separately treat the hydrocarbon layer for the recovery of its alcohol content. If it is attempted to separate the alcohol by washing this material with water, emulsification takes place to such an extent that a clean separation is practically impossible. I find, however, that I can cleanly and efiectively separate the alcohol from such a crude polymer oil by washing the same with a dilute sulphuric acid solution containing preferably from 2 to 10% of sulfuric acid. This strength of acid effectively inhibits the formation of emulsions, While permitting the secondary alcohol to pass into the aqueous layer. The alcohol is then removed from'solution in the dilute sulphuric acid by distillation.

In one particular example, the acid liquor was formed by treatment of a close out butylene fraction with sulphuric acid of about 68%, H2804 content, at a temperature of about 38 C. The acid liquor was then diluted with about 2 /2 volumes of water and left to settle for about three hours. The lower aqueous layer was then drawn off leaving the polymer layer which in thiscase contained about 18% of secondary butyl alcohol. This polymer layer was then agitated with about 3 volumes of dilute sulphuric acid containing about 5% of H2804. After settling for about three hours, the aqueous acid layer contained substantially all of the alcohol Originally in the polymer layer. It was drawn off and the alcohol recovered by distillation.

The foregoing description is for purposes of illustration and not of limitation, and it is therefore my intention that the invention be limited only by the appended claims or their equivalents,

in which i have endeavored to claim broadly all inherent novelty.

I claim:

1. Process of obtaining secondary' alcohols of from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating the said hydrocarbon layer from the said aqueous layer, Washing the said hydrocarbon layer with dilute aqueous sulphuric acid, thereby producing an aqueous sulphuric acid containing secondary alcohol in solution and hydrocarbon material substantially free from secondary alcohol, separating said aqueous sulphuric acid containing secondary alcohol in solution, and recovering the secondary alcohol therefrom.

2. Process of obtaining secondary alcohols of from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating the said hydrocarbon layer from the said aqueous layer, washing the said hydrocarbon layer with dilute aqueous sulphuric acid, thereby producing an aqueous sulphuric acid containing secondary alcohol in solution and hydrocarbon material substantially free from secondary alcohol, separating said aqueous sulphuric acid containing secondary alcohol in solution, and separating the said secondary alcohol by distillation from the said aqueous sulphuric acid.

3. Process of obtaining secondary alcohols of from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating the said hydrocarbon layer from said aqueous layer, Washing said hydrocarbon layer with dilute aqueous sulphuric acid of from 2 to 10%, H2304 content, thereby producing an aqueous sulphuric acid containing secondary alcohol in solution and hydrocarbon material substantlally free from secondary alcohol, separating said aqueous sulphuric acid containing secondary alcohol in solution, and recovering the said secondary alcohol therefrom.

4. Process of obtaining secondary alcohols oi from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating the said hydrocarbon layer from said aqueous layer, washing said hydrocarbon layer with dilute aqueous sulphuric acid of from .2 to 10%, H2304 content, thereby producing an aqueous sulphuric acid containing secondary alcohol in solution and hydrocarbon material substantially free from secondary alcohol, separating said aqueous sulphuric acid containing secondary alcohol in solution, and separating said secondary alcohol by distillation from said aqueous sulphuric acid.

BENJAMIN T. BROOKS.

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